A diesel particulate filter (DPF) traps particulate matter (PM) or soot in exhaust discharged from an engine. With increased soot loading in the DPF, exhaust flow resistance increases, engine performance deteriorates, and the DPF can be damaged.
Accumulated PM can be removed from a DPF using a process referred to as regeneration. Regeneration can be either actively initiated by an engine controller or it can be passively on-going such that a PM oxidation temperature is achieved during normal engine operation (high load leading to engine exhaust above the light-off temperature).